Figure 3 Notation and indexing of patch coordinates xl, patches zxl, and coefficients sixl and in the the corresponding spectra and spectrum, reproduced with permission from Mäkinen et al. (2020). The illustration is for a group of three blocks of size
2×2 at coordinates x1 = (4,3), x2 = (7,5), x3 = (8,6) within a
10×10-pixel image.